From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 600EDC433E0 for ; Tue, 2 Mar 2021 06:49:26 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 08BBA64DE4 for ; Tue, 2 Mar 2021 06:49:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 08BBA64DE4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 719D31663; Tue, 2 Mar 2021 07:48:32 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 719D31663 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1614667762; bh=DLsG+6sfgdq/08NU9Gk5gbRCELe0k6RGOeaWL75YI1A=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=PwdQx8R1uMULAdHyKWg6xD0zyRgH5jc+8BxT0jScVoRvTO6NCiJS7If2H3lODs+RI ttYHtT0EWvA+wuxksy9Ox+ffHBrZmTd0TOxrKU4XcRycDABryR+cLIRua0BcK+u/41 4mGrdiTsipqlvOEweqbEEROe4uWFsjHo4WTXzNKk= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id EFDF2F8025B; Tue, 2 Mar 2021 07:48:31 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 3776CF80269; Tue, 2 Mar 2021 07:48:30 +0100 (CET) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 7C1D3F80088 for ; Tue, 2 Mar 2021 07:48:25 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 7C1D3F80088 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 600B4AC24; Tue, 2 Mar 2021 06:48:25 +0000 (UTC) Date: Tue, 02 Mar 2021 07:48:25 +0100 Message-ID: From: Takashi Iwai To: Anton Yakovlev Subject: Re: [PATCH v6 9/9] ALSA: virtio: introduce device suspend/resume support In-Reply-To: <7d4daea0-ed59-e84c-c28a-945c49204c83@opensynergy.com> References: <20210227085956.1700687-1-anton.yakovlev@opensynergy.com> <20210227085956.1700687-10-anton.yakovlev@opensynergy.com> <7d4daea0-ed59-e84c-c28a-945c49204c83@opensynergy.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Cc: virtio-dev@lists.oasis-open.org, alsa-devel@alsa-project.org, "Michael S. Tsirkin" , linux-kernel@vger.kernel.org, Takashi Iwai , virtualization@lists.linux-foundation.org X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On Tue, 02 Mar 2021 07:29:20 +0100, Anton Yakovlev wrote: > > On 28.02.2021 13:05, Takashi Iwai wrote: > > On Sat, 27 Feb 2021 09:59:56 +0100, > > Anton Yakovlev wrote: > >> > > [snip] > > >> --- a/sound/virtio/virtio_pcm.c > >> +++ b/sound/virtio/virtio_pcm.c > >> @@ -109,6 +109,7 @@ static int virtsnd_pcm_build_hw(struct virtio_pcm_substream *vss, > >> SNDRV_PCM_INFO_BATCH | > >> SNDRV_PCM_INFO_BLOCK_TRANSFER | > >> SNDRV_PCM_INFO_INTERLEAVED | > >> + SNDRV_PCM_INFO_RESUME | > >> SNDRV_PCM_INFO_PAUSE; > > > > Actually you don't need to set SNDRV_PCM_INFO_RESUME. > > This flag means that the driver supports the full resume procedure, > > which isn't often the case; with this, the driver is supposed to > > resume the stream exactly from the suspended position. > > > > Most drivers don't set this but implement only the suspend-stop > > action. Then the application (or the sound backend) will re-setup the > > stream and restart accordingly. > > I tried to resume driver without SNDRV_PCM_INFO_RESUME, and alsa-lib > called only ops->prepare(). It makes sense for a typical hw, but we have > "clean" unconfigured device on resume. And we must set hw parameters as > a first step. It means, that code should be more or less the same. And > maybe it's better to set SNDRV_PCM_INFO_RESUME, since it allows us to > resume substream in any situation (regardless of application behavior). > I can refactor code to only send requests from trigger(RESUME) path and > not to call ops itself. It should make code more straitforward. What do > you say? How about calling hw_params(NULL) conditionally in the prepare? Doing the full stack work in the trigger callback is bad from the API design POV; in general the trigger callback is supposed to be as short as possible. Takashi